International aviation is on course for a rough landing in our warming world. Air travel is growing rapidly -- and so are aviation emissions, which are already responsible for 5 percent of the warming effect of global greenhouse gas emissions.

Despite this bleak picture, the International Civil Aviation Organization, or ICAO -- the United Nations body charged back in 1997 with tackling the airplane pollution problem -- has yet to agree on any measures binding on the industry that would limit emissions.

Getting aviation carbon pollution under control is one of the most important -- and most underappreciated -- battles in the larger struggle to stave off catastrophic global climate change. And politically speaking, there may be only one real hope: America has to stop denying the problem and step up to bat on this critical issue.

That will require a major change of course, since America's airline industry and many American politicians have so far fought bitterly against international efforts to curb pollution. But the Obama administration can and should start demonstrating courage in the fight against climate change at next month's ICAO Council meeting.

The coming months will be critical. ICAO has long reckoned that airlines can stabilize emissions through voluntary technical and operational changes together with the future promise of biofuels.

But such modest efforts won't get the job done. Scientific researchers have found a widening"emissions gap" out to 2050 that demonstrates voluntary measures are insufficient to reduce aviation emissions so that global warming can be kept below 2 degrees Celsius over the next century.

Europe got tired of waiting for ICAO, which is heavily influenced by industry apologists -- and the airline industry itself -- and moved in 2007 to include aviation in the European emissions trading system from 2012. This move isn't perfect, but it is presently the only game in town that has a chance of making a difference for aviation pollution.

But American carriers cried foul, fearing trouble as they are considerably (at least 10 percent) less fuel efficient than their counterparts in Europe, Asia or the Middle East. With the critical help of the Obama administration, they orchestrated a coalition of the unwilling to scupper Europe's efforts.

The coup de grâce was delivered by China, which withheld confirmation of orders for Airbus aircraft. It appears that calls from Airbus headquarters to Paris, London and Berlin late last year did the trick. The European Commission, Parliament and Council dutifully and in record time processed a "stop the clock" law suspending European enforcement of regulations covering intercontinental flights for a year, ostensibly to give time for ICAO to come up with a global solution.

The law took effect recently -- ironically, just as French President Hollande was visiting Beijing together with Airbus to be rewarded by President Xi Jinping with 60 confirmed orders.

With the European trading scheme temporarily defanged, instead of focusing renewed efforts on hammering out a global deal, airline industry lobbyists turned to sidelining the same global action by ICAO they had claimed was needed to make Europe's trading system "fair."

It's hard to see how ICAO can act in the face of the cacophony of opposition. The next meeting of ICAO's Council in June is supposed to miraculously break the political logjam before a key meeting this fall.

Things must change. The Obama administration has to shut the door on industry lobbyists and champion action to control emissions from a global sector that threatens to do long-term climate damage. Such a move should not be a pipe dream. The U.S. is actually making some of the right moves now at the International Maritime Organization on shipping, another major international source of climate pollution.

Airlines also need to wise up. The industry must realise that its mounting contribution to global warming poses a grave danger to its own commercial future no matter how much everyone likes to fly. Indeed, a recent scientific study published in Nature found that climate change will significantly increase turbulence in transatlantic flights, with similar problems likely in other key areas.

Instead, short-termism and a lack of vision has major airlines and their lobbyists working against consensus-building at ICAO while mouthing platitudes about how nice a global deal would be.

Europe says it won't be pushed around and will restart the clock next year if ICAO fails to deliver. If ICAO fails again, we hope that happens. But the prognosis is worrisome.

The U.S. and its coalition insist on limiting any regional emissions regulations to covering international flights only while flying over other countries' sovereign airspace. Such a restriction would leave emissions over the world's oceans completely unregulated and cut the environmental effectiveness of Europe's scheme by two-thirds.

Notably, no such concerns about regulating non-U.S. carriers were voiced in Congress when Kerry/Liebermann proposed a climate law that would have put a carbon price on the full-flight fuel uplifted by all aircraft departing the United States --an approach similar to Europe's.

By pressing the 'airspace' geographical scope on Europe, an approach that contradicts American methods for calculating its own aviation emissions, the U.S. is helping ensure there is no political way forward.

The United States has a political, historical and moral obligation to show leadership. It should work with Europe to broker a global deal that is fair and acceptable to ICAO members and separately agree with Europe, as the two largest global aviation emitters historically, to joint early action across the Atlantic. Time is almost up!

Bill Hemmings is aviation program manager with Transport & Environment.

Vera Pardee is a senior attorney with the Center for Biological Diversity's Climate Law Institute.